Some sanitary installations require the use of a pump to drain water from the installation. For example, in the shower of a boat, it is known to provide an electrically operable pump for draining water from the shower tray. It is undesirable for the pump to be in operation while there is no water in the shower tray. In some cases, therefore, a switch is provided in the shower cubicle for activating the pump, the user being required to hold the switch in an “on” position while the shower is in use. This is inconvenient and so it is also known to incorporate a timer into the switch circuit such that the pump operates for a period of time after activation of the switch and then turns off. However, this can result in the pump continuing to operate for a limited period after the water has been drained from the tray.
It would be desirable to provide a system that overcomes the problem outlined above.